Spontaneous potential log apparatus with randomly occurring noise cancellation

Patent · Tue May 29 04:00:00 EDT 1984

OSTI ID:6529611

Bravenec, F R

In the disclosed and illustrated embodiment, an improved method and apparatus for obtaining an improved spontaneous potential log is set forth. On a single sonde, multiple spontaneous potential electrodes, aligned vertically along the length of the sonde at spaced location, are positioned to transverse a well bore as the sonde is pulled from the well to obtain a measure of spontaneous potential from each electrode. The apparatus and method further discloses means of multiplexing the signals from the several spontaneous potential electrodes whereupon the signals are converted by an analog to digital converter into digital words. By synchronizing with the multiplexing, a digital word is obtained for each electrode at a time such that such electrode is read at a common elevation. The several digital words are then input to delay lines, there being one delay line for each electrode, wherein the delay occurs in multiples of T where T equals the time delay between electrodes. The data is thus time shifted (equal to well depth shifting) so that the spontaneous potential measured at a particular elevation for each electrode is synchronized to thereby permit addition of all the data. Randomly occurring noise is reduced in magnitude. Signals of interest are enhanced compared to the noise.

• Assignee: Halliburton Company
• Patent Number(s): US 4451790
• OSTI ID: 6529611
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
440400 -- Well Logging Instrumentation
47 OTHER INSTRUMENTATION
ANALOG-TO-DIGITAL CONVERTERS
COMPUTERIZED CONTROL SYSTEMS
CONTROL SYSTEMS
DATA ANALYSIS
ELECTRIC LOGGING
ELECTRIC PROBES
ELECTRODES
ELECTRONIC EQUIPMENT
EQUIPMENT
MULTIPLEXERS
NOISE
POSITIONING
PROBES
SIGNALS
SP LOGGING
SYNCHRONIZATION
WELL LOGGING
WELL LOGGING EQUIPMENT